Abstract
Among various biotic stresses, potato virus Y (PVY) is one of the most economically important pathogen deteriorating the quality and yield of cultivate potato (Solanum tuhersosum L.). Precise identification and characterization of PVY in potato tubers is a crucial step for international trade and selection of seed potato for healthy plant material. Nevertheless, PVY genome has high degree of genetic variability and thus detection and classification of isolates is a challenging task. During this study, the genetic variability of PVY was investigated in five different regions of Saudi Arabia. In total, 184 plant leaf samples were collected from Haradh, Qassim, Al-Ahsa, Hail and Wadi Al-Dawasir regions and subjected to PVY specific ELISA assays. The PVY infection rate was ranging from 36.36% in Hail region to 94.47% in the Qassim region, respectively. The strain specific ELISA assay showed that 10.32% of samples were tested positive for PVYN strain while, average rate of PVY infection was 55.98% in all collected samples, respectively. Total RNA was isolated from 25 ELISA positive samples and subjected to RTPCR using degenerate primers for PVY. The amplicons were sequenced and the partial coat protein (CP) sequence of 23 samples were 99.2-100% identical to the recombinant PVY strains SYRII. SYRIII and 261-4, respectively. While, two isolates showed highest nucleotide (nt) sequence identity at 99.7% to PVYN-Wi recombinant strain. The full-length genome of one isolate was completely sequenced using next generation sequencing. which showed 99.4-99.5% nt sequence identity with PVYSVRIII reported from Syria (AB461454) and Saudi Arabia (KP793715), respectively. The results further support the findings that SYRIII strain has been broadly spreading in the Middle East and thus, potato producers in these regions must be well aware of this spreading epidemic in the potato fields.